rotating pictures on the fly

13 May 2007 12:03 AM

JimO

Is there a way in vb.net to, 1) detect if an image has been taken with a
Show quote

> camera on a vertical axis, and 2) rotate the picture for display - across
> an
> intranet (asp.net), with huge files sizes (2 - 3 MB), that doesn't take
> too long?
> (LOL)
>
> Thanks,
> Jim

13 May 2007 1:30 AM

Peter Duniho

On Sat, 12 May 2007 17:03:50 -0700, JimO <joneill517***@XXXearthlink.net>
wrote:

> Is there a way in vb.net to, 1) detect if an image has been taken with a
> camera on a vertical axis, and 2) rotate the picture for display -
> across an intranet (asp.net), with huge files sizes (2 - 3 MB), that
> doesn't take too long?

Unless you are dealing with a camera that has a built-in sensor that
detects orientation *and* the camera stores that information in a custom
EXIF field *and* that data is preserved in the copy of the image you're
looking at, you cannot do #1 without human assistance. I'm not aware of
any available general-purpose algorithm to detect picture orientation
based on the contents alone.

As far as #2 goes, that's pretty simple once you've read the image in.
You can use the Image.RotateFlip() method on a Bitmap that you've loaded
from a file.

I hate to break it to you, but even for compressed JPEGs, 2-3 MB isn't
that big anymore. :)

Pete

13 May 2007 4:24 PM

JimO

I hate to break it to you, but even for compressed JPEGs, 2-3 MB isn't
that big anymore. :)

LOL well... yeah... but I have to display it on a web page. Although, given
the fact it would be accross a a gigabit wire within a small network (like 2
or 3 machines), it may not take that long. One the other hand, I would want
to resize the display to a thumbnail image (like maybe 200x300) onto kind of
a contact sheet. When paging through them, that might take a while if there
are more than a few per page. The camera would be either a Nikon D50 or a
D200. Other software I use will rotate the image, when needed, so, I
know the info is in there somewhere.

Show quote

"Peter Duniho" <NpOeStPe***@nnowslpianmk.com> wrote in message
news:op.tr8rs7bw8jd0ej@petes-computer.local...
> On Sat, 12 May 2007 17:03:50 -0700, JimO <joneill517***@XXXearthlink.net>
> wrote:
>
>> Is there a way in vb.net to, 1) detect if an image has been taken with a
>> camera on a vertical axis, and 2) rotate the picture for display -
>> across an intranet (asp.net), with huge files sizes (2 - 3 MB), that
>> doesn't take too long?
>
> Unless you are dealing with a camera that has a built-in sensor that
> detects orientation *and* the camera stores that information in a custom
> EXIF field *and* that data is preserved in the copy of the image you're
> looking at, you cannot do #1 without human assistance. I'm not aware of
> any available general-purpose algorithm to detect picture orientation
> based on the contents alone.
>
> As far as #2 goes, that's pretty simple once you've read the image in.
> You can use the Image.RotateFlip() method on a Bitmap that you've loaded
> from a file.
>
> I hate to break it to you, but even for compressed JPEGs, 2-3 MB isn't
> that big anymore. :)
>
> Pete